Re: Diesel truck guys.....
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Maelek</div><div class="ubbcode-body">im not saying to use the instant. I am saying to use the average. But you have to clear it once you get on the highway at the speed you want to check it at
you cannot hand calculate it unless you are ok with taking into account the stops and starts and accelerations to get from the gas station onto the interstate then off the interstate to the next gas station for the fillup.
All of this is really just pissing in the wind since no one hops into their vehicle and immediately on the interstate with no stops, starts, accels, decels, up hills, down hills, etc.
thats why i said you have to take it with a grain of salt when you figure out the best possible miles/gallon because you dont get that as a rule.</div></div>
If you are trying to figure out what your mpg's are, you have to figure it all in.
ALL of the mpg displays are bullshit, nowhere close to right in most cases and they seem to be even further off when it comes to diesels. When I fill up my tank and the pump stops I can fit another 3-4 gallons in it because Dodge doesn't know how to properly vent a tank. I spend 10 minutes after the pump automatically shuts off drizzling fuel into my tank and watching the foam rise and fall in the filler neck of my tank until the foam stops and I have diesel sitting all the way up to the top of the filler neck. I then have to rock my truck back and forth to get the fuel in the filler neck to settle just enough that I can put the cap on without making it overflow down the side of my truck.........So I KNOW how much fuel is in my tank when I leave the gas station. I was sitting at just over 1/4 tank when I left work today and decided to swing by and fill up on my way home. At every fill up I zero out my trip odo and my mpg calculator in the overhead before I leave the gas station. On this tank my overhead showed that I averaged 18.4 mpg since last fill up, hand calculating it reveals another story....393.7 miles / 26.88 gallons = 14.65mpg, which means my overhead is off by over 25%. I'd just as accurately have a monkey throw a dart at a number as put stock in the overhead calculations.
I keep record of every drop of diesel and every mile at fill up, every oil change, fuel and air filter change, etc. in a log book like a pilot would do. I hand calculate at each fill up the same way. I'd have to look it up what the best mpg's I've gotten on a tank, but two come to mind. One was driving from memphis to northern indiana with a stiff tailwind and I was around 22-23mpgs. The other was driving from memphis towards pittsburgh and making it just west of wheeling, wv without running out of fuel, just shy of 700 miles and my tank holds 34 gallons per the manual. The pittsburgh trip was a few months after I bought my truck which was before ULSD was in the pumps, the old LSD was much better stuff by my calculations.
